There exist various types of vehicles used mainly in off-road conditions. One such type is the side-by-side off-road vehicle. The name “side-by-side” refers to the seating arrangement of the vehicle in which the driver and a passenger are seated side-by-side. Some side-by-side off-road vehicles also have a second row of seats to accommodate one or more additional passengers. These vehicles typically have an open cockpit, a roll cage and a steering wheel.
To be able to operate in off-road conditions, a side-by-side off-road vehicle needs to be able to handle bumpy terrain to operate on various surfaces including, but not limited to, sand, dirt and mud. These conditions represent unique challenges not typically encountered when designing on-road vehicles such as cars. One such challenge is that the amount of travel of the suspension systems is generally greater than in on-road vehicles such as cars in order to handle the bumpy terrain.
Furthermore, side-by-side off-road vehicles are generally narrower and shorter than on-road vehicles such as cars. As such, there is less room for all the vehicle's components such as the steering system. In the steering system, having a long steering column increases the chance that the steering shaft will interfere with other components such as the suspension.
One solution used to accommodate the steering system consists in having a steering column made of multiple shafts connected to each other by articulations such as universal joints. However, having a lot of articulations usually results in more angle changes between the steering wheel and the rack and pinion assembly used in some vehicles due to play in the articulations. Therefore, the rack of the rack and pinion assembly moves less than it should for the amount by which the steering wheel is turned. Also, as the number of articulations increases, the force required to rotate the steering wheel also increases.
Furthermore, the tie rods connecting the rack of the rack and pinion assembly to the wheels are connected to the ends of the rack. While this helps prevent any contact between the tie rods and the rack and pinion assembly as the tie rods pivot with the travel of the wheels, the resulting tie rods are relatively short. Having short tie rods causes bump-steer as the wheels travel from their normal rest positions. Although the amount of bump-steer is minimal for a small amount of travel, this amount increases as the wheels travel more and becomes unacceptable beyond a certain amount of wheel travel. As such, the design of the front suspension assemblies has to be a trade-off between the amount of travel of the wheels and the amount of bump-steer resulting from the short tie rods.
Therefore, there is a desire for a steering system that has few articulations, is unlikely to cause interference with other components of the vehicle and permits large amounts of travel of the front wheels.